This is a very, very old antique shut off knob - we are unaware as to what antique appliance or application it was used on - it was in boxes of vintage stove parts we purchased several years ago and we thought it was very interesting. Please view ALL photos and be sure it and the condition is as pleasing to you as it was to us prior to making your purchase. Drop a note with any questions, we're happy to help. 

MEASUREMENTS: Approx Underside Stem: 2-3/4"    Knob Diameter 2.0"